This invention relates generally to circuit protectors and more particularly to a combination arc fault circuit interrupter and ground fault circuit interrupter (AFCI/GFCI) having a single test button for fully testing both the ground fault and arc fault detection circuits of the circuit protector.
Ground fault circuit interrupters are well known in the prior art. Recently, there has been a demand for arc fault circuit interrupters that detect arcing on an electrical circuit and remove power from the circuit in response to the presence of arcing. Combination ground fault circuit interrupters and arc fault circuit interrupters respond to this demand.
Ground fault circuit interrupters conventionally include a test button for testing the ground fault sensing circuits and circuit interrupting circuits. Test circuits for testing an arc fault sensor and circuit interrupter also exist. Providing both arc fault circuit interrupter testing functions and ground fault circuit interrupter testing functions in combined devices is important for providing a practical device. Relying on two separate test circuits with two separate test buttons is cumbersome and inefficient and may not be acceptable to customers.
Accordingly, it is an object of this invention to provide a combination AFCI/GFCI having a single test button which when activated, fully tests both the ground fault and arc fault detection circuits and the interrupter circuit in the combination AFCI/GFCI.
Briefly stated, and in accordance with the presently preferred embodiment of the invention, a combination AFCI/GFCI includes a single test button which when activated, tests both the arc fault and ground fault detection circuitry and the circuit interrupter. Preferably, closing the test button causes a simulated ground fault and enables a signal steering circuit. The steering circuit redirects the ground fault detector output to an arc fault simulator circuit which produces a simulated arcing pulses that are coupled, preferably by way of an extra winding, to an arc fault sensor transformer. The arc fault detector senses the arc fault simulator pulses coupled to the sensor transformer and, if everything is operating normally, triggers a switching device such as an SCR which activities a circuit interrupter. In this way, both the ground fault circuit interrupter and arc fault circuit interrupter functions are tested simultaneously, and the test is initiated by a single test button. When the circuit interrupter is not in the test mode, the steering circuitry allows either a ground fault or an arc fault or both to independently activate the switching device and the circuit interrupter.